Morphometric characteristics of lake bottoms of Lakes CHarskoe and Nuksenskoe (Volga upland, Russia) as the basis of their classificationAndrej Astashin, Ekaterina Nikolaeva, Nikolaj Bayanov, Ol'ga Vatina and Mihail BadinE3S Web Conf., 431 (2023) 04004DOI: https://doi.org/10.1051/e3sconf/202343104004